budesonide is #1 which is used to treat asthma (in puffers I believe).
I spent some time scraping medication information and learned that pharmacies in the US mine massive amounts of data about pharmaceutical purchases and there are a few billion dollar companies that collect/sell this data. Customer information is "anonymized" of course at the pharmacy level. You can find the sales of the top 100 drugs drugs pretty easily online, but there are thousands of drugs and the data-mining companies charge you to see sales of the smaller ones (from my experience).
You are correct! Budesonide is available as a generic inhalable steroid for asthma.
As for Rx data, IMS is king. They pay pharmacies, wholesalers, etc to report all of their sales. It's used heavily by pharma companies. I've seen some of the data and it goes all the way down to individual Rxs by doctor. Incredible stuff.
It's about 1/2 way down the page. Of course this is by total number of Rxs, not dollars. Hydrocodone/APAP is pretty cheap. Also it's from 2012, so it might have changed.
